Everyone can and should strength train at least 2x a week. No matter your fitness level, or what type of dysfunction or injury you may have had it can be safely worked into a program when working with an exercise professional and will be beneficial 

6 Reasons why everyone should strength train: 

1. Increases Bone Density. This is especially important for us ladies who are prone to lose bone density as we age and are at higher risk for osteoporosis. So ladies, do not be afraid to lift heavy, its going to benefit you in the long run!
2. Increased Muscle Mass. Not only does muscle protect your joints from injury, but it is also an important part of rehabilitating an injury. In any rehab program we focus on building up the muscle around the joint safely to prevent further damage. It also burns more calories even when you are at rest. With more lean muscle mass, you`re less likely to injure yourself and in the long run it helps you lose weight if you have more muscle. 
3. Greater stamina, youre going to get stronger and better ability to perform. For example, going for a hike that seems strenuous may seem easier after a 6 week strength program. 
4. Better sense of well being. Any sort of exercise releases endorphines and has been shown to improve mood, this is great news for anyone who suffers from anxiety or depression. This can help improve body image, as well as your self confidence. 
5. It will NOT make you bulky. I have been strength training for a few years now, my body has definitely changed size and shape but I do not look bulky or manly in any way. 
6. It helps with control and prevention of some diseases. It helps those with diabetes control their glucose levels and is helpful in prevention of cardiovascular diseases

Side effects: Can make you feel like a motherfucking badass. Lifting heavy things can give you a sense of accomplishment when you reach new goals and add more weight! So get out there and lift the big weights, and feel amazing.